Thoracoabdominal surgeries, including abdominal aortic aneurysm repair, aortic dissection repair, and aortic thrombectomy, are associated with substantial neurologic morbidity. During abdominal aortic aneurysm repair, for example, an arterial clamp is placed across the aorta for total occlusion and the abdominal aorta is incised or transected for repair. The iliac, the superior mesenteric, and the spinal arteries are often ligated at their origins from the aorta. As a result, spinal cord ischemia can occur in up to 30% of patients. Spinal ischemia is caused partly by lack of blood flow to the spinal cord during aortic clamping, and partly by embolization from the aorta into the spinal arteries.
To reduce the incidence of peri-operative spinal ischemia, several devices were developed to maintain perfusion to the spinal arteries during thoracoabdominal surgeries. Moses describes an internal aortic shunt which perfuses the distal aorta. However, the shunt fails to specifically perfuse the spinal arteries. An intravascular device was described in Rom et al., U.S. Pat. No. 5,746,709, incorporated herein by reference, which involves an intra-aortic pump. Disadvantages associated with this device are that (1) puncturing of the aorta is required for inserting an occluder, (2) arterial clamping is required, which carries the risk of thromboembolism, (3) the aorta needs to be incised for inserting catheters into the spinal arteries.
Rayhanabad developed a single component device for spinal perfusion during aortic surgeries. However, the device cannot be inserted prior to severing of the aorta and therefore failed to eliminate the need for aortic cross clamping and puncture. Khorasani describes an external shunting system with branches to perfuse the spinal arteries through the aorta. However, this system still requires aortic clamping and perforation.
According, there is a need for devices and methods which provide perfusion to spinal arteries during thoracoabdominal surgeries, and reduce neurologic complication by obviating the need for aortic clamping and puncture.